Robin boundary condition

Robin boundary condition is a way of understanding how things move between two boundaries. Imagine you have a round circle with a line across it. The Robin boundary condition is all about what happens when something moves from one side of the line to the other side. The Robin boundary condition tells us that when something moves from one side of the line to the other side, it can only move in certain ways. It can either move freely, like a ball bouncing back and forth between two walls, or it can go in a certain direction and stop. The direction that it stops will depend on the Robin boundary condition.